Telegraph system and apparatus for selective single or double channel operation



2,418,928 INGLE on W. R. GEMMEL April 15, 1947.

TELEGRAPH SYSTEM AND APPARATUS FOR SELECTIVE 5 DOUBLE CHANNEL OPERATION5 Sheets-Sheet 1 Filed Nov. 4, 1944 INV ENTOR L E M M E G R R UWAZIQRNEY April 15, 1947. 2,418,928

ECTIVE SINGLE OR BLEOHANNEL OPERATION Filed NOV. 4, 1944 W. R. GEMMELTELEGRAPH SYSTEM AND APPARATUS FOR SEL DOU 3 Sheets-Sheet 2 INVENTORWILBUR R. GEMMEL BYZ RNEY 7 ATTO April 15,

1947. w GEMMEL I 2,418,928 TELEGRAPH SYSTEM AND APPARATUS FOR SELECTIVESINGLE OR DOUBLE CHANNEL OPERATION Filed Nov. 4, 1944 3 SheetsSheet 3INVENTOR W ILBUR R. GEMMEL T'TORNEY Patented Apr. 15, 1947 'UNlTE.

TELEGRAPH SYSTEM AND APPARATUS FOR SELECTIVE SINGLE OR DOUBLE CHANNELOPERATION Wilbur R. Gemmel, Wheaton, Ill., assignor to TeletypeCorporation, Chicago, Ill., a corporation of Delaware ApplicationNovember 4, 1944, Serial No. 561,874

Claims.

This invention relates to start-stop multiplex telegraph apparatus andmore particularly to transmitting apparatus for multi-channel operation.

The normal use of start-stop telegraphic communication apparatus haspreviously usually been limited to the transmission of a single messagein one direction over a single channel at any one timg The result of uchoperation tends to decrease the maximum possible message transmissionover a single line, and thereby results in an incomplete use of asignaling channel.

Telegraphic systems have been operated over what is known as atwo-channel system. In this operation the messages are doubled by use ofapparatus so that two messages may be sent by start-stop apparatus inthe time previously utilized for the transmission of a single message.However, in such a system it has been necessary to reduce byapproximately one half the length of time allocated to each of theindividual impulses constituting the five unit Baudot code signals. Theresult of the decrease in the impulse interval has been that under poorsignaling conditions, such as static in radio transmission, the shorterduration impulses will be lost, and therefore an error will result inprinting at the receiving station. Therefore, it becomes necessary toeither stop transmission completely during times of poor signalingconditions, to use a separate standard single channel transmitter tosend out only a single message over one channel, or to provide apparatuswhereby two-channel transmission may be utilized during times of goodsignaling conditions and single channel operation during time of poorsignaling conditions.

Accordingly, the primary object of this invention is to provideapparatus which may be operated to transmit in two-channel operation orin single channel operation, depending upon the setting thereof.

Another object of the present invention is to provide a means wherebyeither or both of the transmitting units comprising the components oftwo-channel transmitting apparatus may be prevented from furthertransmission.

-A further object of the invention is to provide either neutral or polarsingle or two-channel operation. A still further object of the presentinvention is to provide, during polar operation, means whereby when oneof the transmitters is stopped, 9, letters combination rather than theconventional blank combination will be transmitted over the signallingchannels.

This latter object is important when the apparatus is used in systemswherein the blank combination is utilized as a switching or stationselecting combination.

A more detailed understanding of the invention may be had from thefollowing description with reference to the accompanying drawingswherein similar numerals indicate similar parts, in which:

Fig. 1 is a perspective view, partly broken away, disclosing theapparatus embodying the invention including two tape transmitters and anassociated distributor;

Fig. 2 is a schematic View disclosing the electrical circuit of theapparatus for neutral signaling and certain mechanical parts associatedtherewith;

Fig. 3 is a schematic view, showing part only of a polar electricalcircuit and certain of the mechanical element associated therewith;

Fig. 4 is an enlarged elevational view showing an operationalrepresentation of the apparatus associated with one of the tapetransmitters for shifting from two channel to single channel operation,and also the device for individually stopping one of the tapetransmitters; and

Fig. 5 discloses a modification of the apparatus for shifting from twochannel to single channel operation.

The present apparatus comprises two tape transmitters connected to adistributor in such a manner that the impulses making up the codesignals will be transmitted in alternate sequence by-the distributor. Aswitching lever is provided which causes the bail of one of the tapetransmitters to be locked in its unoperative position and which at thesame time tie-energizes a relay to open the connections of thistransmitter to the distributor. That is, when the switching lever isthrown and the relay de-energized, electrical circuits are establishedso that instead of transmitting two messages over half length segments,a single message will be transmitted over normal or full lengthsegments. Stop levers are also provided, individually associated witheach of the tape transmitters, so that upon operation they will causethe ball of the associated tape transmitter to be locked in such aposition that the tape transmitter will be rendered unoperative.

Referring to Fig. 1, the apparatus disclosed therein is also shown inBulletin No. 1119, published in March, 1944, by the TeletypeCorporation, Chicago, Illinois. The use of two tape trans-' mitters inconjunction with a single distributor is disclosed, substantially asshown in the present invention, in U. S. Patent No. 2,231,375 issued toE. F. Watson on February 11, 1941.

Specifically with reference to Fig. 1, the transmitting apparatuscomprises two tape transmitters designated A and B and a distributorindicated generally by the numeral ll. Transmitter A comprises a seriesof five feeler levers l2 which are each pivoted about a pivot rod l3 andeach of which have a tape sensing pin I l at their forward end. Each ofthe feeler levers l2 is biased in a counterclockwise direction by meansof individual springs l6 connected near the rearward end of the feelerlevers l2. An extension I! is provided at the extreme rearward end ofeach of the feeler levers 12 which serves as the movable contact of anelectrical contact switch formed of individual upper contacts l8 andlower contacts 19. Set screws 26 are provided for both the upper andlower contacts !8 and I9 so that the contacts may be individuallyadjusted with respect to the movable contact-arm ll, associatedtherewith. The individual. springs I 6 are connected at their lower endsto lugs 22, one of which is individual to each of these springs andwhich are all-mounted on an insulated panel, 23. A sixth lever isprovided, whichislalso pivotally mounted on the rod l3, and which doesnot have an electrical contact assosiated with its rearward end but doeshave a, pivoted pawl 26. mounted at the forward end thereof. A ratchet2? is mounted adjacent the pawl 2ton a shaft 28, said shaft havingmounted securely thereon, in proximity with, the feeler pins M; a, tapefeed wheel 29 which is provided to intermittently step the tape utilizedin the transmitting apparatus a distance between adjacent transverserows of perforations during operation of the mechanism. The tape feedwheel 29-and the ratchet 27 areboth securely fastenedto the shaft 28,which is rotatively mounted in the framework of the apparatus sothatupon motion to the ratchet 2?, through the operation of the pawl 26,the tape. feed wheel 29 will be rotated to step the tape.

Each of the feeler levers l2has a downwardly extending projection 3i, infront of which is pivotally mounted a, bail 32 on a shaft 33. .Thetapefeed lever 25 has a similar downwardly extending arm (not shown), alsoengageable by thebail 32. The bail 32 has a downwardly extending lug 35which is provided to cause the bail to operate in a manner which will bedescribed hereinafter. The mechanism which hasbeen described above, withrespect to tape transmitter A, is standard equipment and may be morefully understood by referring to Bulletin No. 141 issued in March1942,1oythe Teletype Corporation, Chicago, Illinois.

Briefly, the operation of the mechanism, as is well'known in the art,consists in a tape bein passed over the tape feed wheel 2-9 and thefeeler pins [4 of the feeler levers l2; The individual springs iii ofthe feeler levers I2 normally urge the levers in a counterclockwise.direction, so that, assuming that the bail 32 is not blocking the feelerlevers l2 by engaging-their downwardly extending portions 3|, the pinsl4-will be allowed to sense the tape and, if there is a perforation inthe tape at that point, will pass therethrough. The result of a pin 14passing through the associated perforation in the tapeis to cause thecontact arm I! associated with that particular pin M- andfeeler arm I2tov come into engagement withthe lower electrical contact If), thereby.establishing a circuit for a markingcimpulse to be transmitted over theline conductor, in conjunc 4 tion with the distributor H as will bedescribed hereinafter. In the event that there is no perforation in thetape opposite a particular pin M, the pin it will not be able to moveupwardly and the associated feeler lever 12 will not be allowed topivotin a counterclockwise direction, which results in the contact arm l!associated with that particular feeler lever i2 not being moveddownwardly, but instead being held in engagement with the upperelectrical contact iii. The absence of a perforation in the tape and theengagement of the contact arm I! with the upper contact it! results, inconjunction with the distributor H, in a spacing condition beingestablished'on the line conductor. After a complete signal has beentransmitted, later to be described, which includes the movement ornonmovement of all five feeler levers E2, the bail 32 will be operated,through its lug 34, pivoting in a counterclockwise direction as viewedin Fig. 1, causing its upper. rear surface to engage the projection 31extending: downwardly from each ofrthe. fivev feeler levers l2- and thetape feedlever 25. Such.

movement on the part of the bail 32 causes the feeler, levers l2, andthe tape lever 25 to be rotated in a clockwise direction, causing thefeeler pins M to be removed from any perforation in the tape that theymay have sensed. At the same time the tape feed lever 25 is also pivotedin a clockwise direction and pawl 28 moved downwardly, which resultsinthe ratchet Zlbeing rotated a corresponding amount. 2lrotates apredeterminedamount, the rod 28 is rotated which causes tape feed wheel29 to ,move a corresponding amount. This last movement causesthe tape(not shown) to be moved a distance which is equal to that of thedistance between adjacent transverse lines of perforationsin the tape.Immediately after this occurs, pressure will be released from the lug fil of the bail 32, the bail then being free to move in a clockwisedirection under the urging of the projections 3| through-the action ofthe feeler levers l2 and the springs l6. Thus, the pins Mare now free tosense the next row of perforations in the tape. The above operationrecurs automatically as long as the operating means for the bail lug 34work or until such time as the bail 32 may be prevented from moving, aswill be described hereinafter.

Associated withthe tape transmitter A is a three. armed lever, indicatedgenerally by the numeral 35, pivotally mounted at 31, and having anupwardly extending arm 35, a forwardly ex tending. arm 35, and a shortdownwardly extending arm. 49. A pin '32 extends outwardly from theupwardly extending arm 38 andhas a-spring 33 connected thereto. Theopposite end of the spring 83. is fastened to a pin id extending from anarm 45 which is securely fastened to the apparatus frame and extendsrearwardly and downwardly. The spring is and the arm dd-act as-anover-throw device with respect to the three armed lever 3%: A stop pintitis provided in association with-the short downwardly extending arm 40whereby the counterclockwise movement of the three armed lever 3% islimited to a predetermined distance.

Pivotally mounted on a shaft 5? is a rearwardly extending lever it. Thelever-43 has a sidewardly extending lug dd-which extends far enoughsidewardly so as to be in the path of the forwardly x en arm 39 of the.three armed lever 36, and is operated about its pivot rod 4.! inthelevent that the leveri-idis moved in.a,clockwise direc- As theratchet anaeaaw.

tion. The lever it has a downwardly extending portion .52 which normallyis in engagement with the upper contact spring 53 of an electricalcontact'pair formed with a lower contact spring 54. Thus, in the eventthat the three armed lever 36 is operated in a clockwise direction, theforwardly extending arm 39 will engage the sidewardly extending lug 50of the lever 58, thereby causing the lever 48 to be pivoted in acounterclockwise direction, causing the portion 52 thereof, inengagement with the upper contact spring 53, to move the spring contactdownwardly into engagement with the lower contact spring 54. All of theabove apparatus, which has been described for the tape transmitter A isidentical in tape transmitter B. Therefore, for purposes ofsimplification, the parts in transmitter B have been labeled withnumerals similar to those in tape transmitter A. Hereinafter throughoutthe specification, reference will be had to specific parts by giving thenumeral and then identifying to which of the tape transmitters mentionis being made.

It is to be noted that the bail 32 is provided with a forwardlyextending upper lip 56, and that the lever 48 is provided with a notchor shoulder therein, which corresponds with and engages the forwardlyextending lip 56 of the bail 32 under certain operating conditions.

In the tape transmitter B the lever id is not a single arm lever, butinstead is one arm of -a bell crank lever, the opposite arm 49 of whichextends downwardly. The bell crank lever is pivotally mounted on theshaft til. Other than for the noted difference the levers A8 of thetransmitters A and B are identical and perform a similar operation, aswill be described hereinafter.

Also associated with tape transmitter B but not with tape transmitter Ais a lever 58, extending leftwardly and rightwardly, as viewed in Fig.1, pivotally mounted at 59 and having an upwardly extending arm sotoward the left and a pair of upwardly extending flanges 6! at the rightextremity thereof. A spring 62 is provided which is secured at one endto the bottom of the downwardly extending arm 45 of the bell crank leverpivoted at 41 and has its opposite end pass through an opening at thetop of the upwardly extending arm 60 of the pivoted lever 58. After thespring passes through the opening in the arm til it is bent downwardly,as shown at 63. The connection is such between the spring E2 and the armGil that if the lever 58 is pivoted in a counterclockwise direction thespring 62 will be extended, whereas if the lever 58 is moved in aclockwise direction a straight section of the spring material willmerely pass through the opening in the arm 66. The upwardly extendingflanges El of the lever 58 control, the operating arm as, of a toggleswitch indicated generally by the numeral 66. The toggle switch 86 hasan operated arm 6i extending from the opposite side thereof which ispositioned in engagement with one contact arm 68 of a contact pairformed with an opposite contact arm 69. The contact arm -68 is formed insuch a manner that if the toggle switch 85 is operated from normalposition, the operated arm 61 will cam the contact arm 68 intoengagement with the contact arm 69.

The apparatus described immediately above is utilized in the switch-overoperation so as to achieve either single or two-channel transmis- 'Thedistributor generally designated by the numeral ll comprises a faceplate H having a solid ring l2 and a segmented ring; 13, concentrictherewith, with a brush arm 24 traveling over and bridging electricallythe rings 12 and 13. The brush arm 14 is securely fastened to a shaft 16onwhich is also securely fastened a gear H. The gear TI is driven bymeans of a pinion connection with a motor, neither of which are shown,in order to rotate the shaft and consequently the brush, over the rings12 and 13. Positioned at the bottom of the shaft 16 is a earn it havinga high portion Til thereon.

By referring to Fig. 2 it may be seen that the segmented ring '13 isformed with a start segment 81, ten code segments 82, av stop segment83, and a small segment 84 which is one half the size of the codesegments 82, the utility of which will be described hereinafter. Thecode segments 82 are approximately one half the size of the normal codesegments as used in a single channel start-stop transmission system.Each of the segments 8!, 82, 83, and 84 are insulated.

from their adjacent segments. The ten code segments 82 are connected inan alternate sequential order to the five contact lugs 22 of transmitterA and to the five contact lugs 22 of transmitter B. That is, one codesegment 82 is connected to lug 22 of transmitter B and the adjacent codesegment 82 is connected to a similar lug 22 on transmitter A. In orderfor the two complete code signals to be transmitted, one fromtransmitter A and one from transmitter B, the brush arm l l must rotateover all of the code segments e2. Thus, it may be seen that when thebrush arm "id makes a complete revolution two individual signals will betransmitted over the line conductor on two-channel operation. whereaswith the usual standard system the brush arm would rotate one revolutionand send one code signal only. Two channel transmission is described inthe above-mentioned patent to Watson.

Cooperating with the cam 18, Fig. 1, is an operating lever 86 which hasa follower roller 81 extending therefrom which engages the periphery ofthe cam 58 and thereby controls the operation of the lever 86accordingly, the lever 86 being pivoted at 83. The operating lever 86has an extended portion 89 which is adjacent to the downwardly extendinglug 3d of the bail 32 of transmitter A and separated therefrom by anadjustable set screw 9% secured in the portion 89, the latter of whichcontrols the operation of the bail about its pivot rod 33 in accordancewith the movement of the operating lever 86 about its pivot 86.

An arm 9! having a bifurcated forward end is securely connected to theoperating lever 86 in such a manner that the bifurcations straddle thepivot point 83. A connecting link 92 is pivotally mounted at 93 to thearm 9|, said link extending from transmitter A to transmitter B. At theopposite end of link 92 (transmitter B), pivotally connected at 94, isan arm similar in design to the arm 9! and also having a bifurcatedforward end. An operating lever 97, pivoted at 98, is securely fastenedto the bifurcated portion of the lever 95 in such a manner that thebifurcation straddles the pivot pointQS. An extended portion 99 of thelever 91 is associated with the lug 34 of the bail 32 of transmitter Bbut separated therefrom by an adjustable set screw lllfl. Thus theoperating lever 91, through its extended portion 99 and set screw Hill,controls the operation of the bail 32 of transmitter B.

From the structure just described it may be seen that each of the bails32 of transmitters A and B are under the control of their associatedoperatin levers 86 and 91, respectively, both of which are under thecontrol of the periphery of the cam 78; Thus, at such time as the cam-78 rotates to present its high portion 79 or its opposite low portion tothe camfollower roller 81, thus controlling the operation of theoperating lever 86, the bails of transmitters A and B will be operatedaccordingly.

It isto be further noted that the extended portion 89 of the operatinglever 86, which is associ ated with the lu 34- of the bail 32 oftransmitter A, has fastened thereto an insulated section IIlI which atits opposite end controls a movable elec trical contact spring IEIEL Theelectrical contact spring I92 acts as the common spring contact withrelation to contacts I03 and I04, one of which is positioned to eachside of the spring contact I02. Thus, when the operating lever 86 withits extended portion 89 is moved under the control of the cam '58, themovable contact spring Hi2 will be positioned either in engagement withthe associated electrical contact IE3 or I84, depending on whether thehigh or low portion of thecam T3 is presented to the follower roller Bl.

Byreferring now to Fig. 2, it may be seen that the contact lugs 22 oftransmitter B are connected electrically by conductors it, througharmatures Ifi 'i (when their associated relay is energized), and throughconductors I08 to the first, third, fifth, seventh, and ninth codesegments 8 20f the segmented ring I3. Likewise, the con tact lugs 22' oftransmitter A are connected electri'caily over conductors I II] to thesecond, fourth, sixth, eighth, and'tenth code segments 82 of thesegmented ring 73. The contact arms i! are electrically connected to thelugs 22 through the springs I 5. Thus, it may be seen that the two tapetransmitters are connected in alternate sequential order tothe segmentedring l3, as previously mentioned.

It may also be seen (Fig. 2) that the electrical contacts is of bothtransmitters A and B are connected to a grounded battery III through acommon conductor H2. A conductor H3 extends from the common conductorII2 to the stop segment 83 of the segmented ring 13. A short branchconductor H4 extends from the conductor H3 and supplies potential fromgrounded battery Iii through the common conductor II2, the conductorII3, the short conductor H4, an armature H3 (when attracted by relayI33), and a conductor II! to the small segment 34 of the segmenteddistributor ring 53. A conductor H8 extends from the start segment 3I ofthe segmented distributor ring 73,

and under the condition shown in Fig. 2, establishes an electricalcircuit through the unattracted armature lit, over the conductor II'l,to the small segment 84.

In considering normal operation of the apparatus, as disclosed underneutral signal conditions of Figs. 1 and 2, it may be seen thatordinarily when the device is in its stop position a marking conditionwill exist on the line which results from the clockwise rotation of thetwo levers 3:3 and the closing of the associated contacts 53 and 54*, ina manner and over a circuit to be described hereinafter.

In the operation of the apparatus, let us assume that it is desired totransmit, upon starting, over the two channels. Prior to any operation,the three-armed lever 35 associated with each of the tapetransmitters'is manually moved to its maximum clockwise-position, whichwill causethe bails 32 to be blocked and the tape After the shaft I6 hasrotated sufiiciently to allow the brush arm 14 to be brought tooperating speed, the three-armed levers 36 are positioned manually in acounterclockwise direction, and the tape transmitters are renderedoperative, to be hereinafter described.

Referring to Fig. 2, it may be seen that simultaneously with theoperation of the switch-over lever 58, the upwardly extending flanges 6|at the rightward extremity thereof will cause the operating lever 34 ofthe toggle switch 66 to be moved in a counterclockwise direction,thereby resulting in the operated lever Gl' camming the electricalswitch arm 68 into engagement with the stationary electrical switch arm69, closing the electrical contact at this point. Assuming that the highportion of the cam 79 is in engagement with the follower roller 31',which occurs when the brush arm I4 is on the stop segment t3, theoperating lever 86 will be pivoted about pivot point 88 in acounterclockwise direction, causing the extended portion 89 to be movedin a counterclockwise direction, and the movable contact swinger Hi2connected to the extended portion fill by means of the insulatedsecuring member Ill! to likewise be moved in a counterclockwisedirection. This results in the movable swinger I62 being positioned inengagement with an electrical contact HM. Thus, an electrical circuit isestablished which may be traced from the local D; C. source IZI (Fig. 2)over conductor I22 to junction point I23, over conductor I24, throughmovable electrical contact arm 68, through the electrical contact arm69, through a conductor I26 to junction point I21, through a conductorI25 through the movable swinger arm I62, through the electrical contactI94, through a conductor E29, through a conductor I3 I, through a conductor I32, through the coil of the relay l33, through a conductor I34having a resistance therein, and back to the D. C. source I2I.

The result of the electrical circuit just established is that the relayI33 will be energized, resulting in its associated armatures H3 and I01,previously mentioned, being attracted thereto, as is also an armatureI38.

' Upon the armature I36 being attracted, due to the energization of therelay I33, a locking circuit is established for the relay which may betraced from the D. C. source I 2I, through the conductor 122, throughthe conductor I 24,

through the now closed contact pair comprising the contact arms 68 and39, through the conductor I26 to junction point I 27, through aconductor i3l, through the armature I36, through the conductor i3I,through the conductor I32, through the coil of the relay I33, andthrough the conductor I34 to the opposite potential of the D. C. sourceI 2i;

It is to be remembered that in the above description we assumed that thecam I8 was so positioned that its high point 79 was in engagement withthe cam follower roller 87. In the event that the brush arm 14 were inany position other than in engagement with the stop segment 83, the cam18 would be so positioned that its high portion I9 would not bepresented to the cam follower roller 81- Under such a condition theoperating lever 85 would be in a clockwise position, as viewed in Fig.2, and its extended portion 89 would likewise be so positioned resultingin the movable swinger arm I02 removed from engagement with contact I04,and instead positioned in engagement with the contact point H13. Thus,there would be no electrical circuit completed for the energization ofthe relay I33 inasmuch as in the unenergfzed condition of relay I33 thearmature I36 would be in normal open position, as shown in Fig. 2, andno circuit could be traced from the D. C. source I2I. The only time thatthe relay I33 will become energized is when the brush arm M is inengagement with the stop segment 83 as the circuit therefor is traceablethrough the contact IM. This provision has been made to cover apossibility which will be referred to hereinafter.

As previously mentioned, upon the energization of the relay I33. thearmatures HS and IllI are also attracted thereto. As a result of theattraction of the armature H6 a circuit may be traced from groundedbattery III, through conductor H2, through conductor H3, throughconductor H 3, through the armature H5, over conductor H'I, through thesmall segment 8G, over the brush arm 14, through the solid ring I2, andover the line conductor H9. The results of battery being extended to thesmall segment 84 acts as an increase in the length of the stop segmentand thus of the stop impulse on the line conductor H9. Inasmuch as whenthe unit is in operation the tape spacing operation occurs while thebrush arm 14 is on the stop segment, it is necessary that the stopsegment and its corresponding impulse be of a certain duration. It is tobe understood that the above condition prevails during double channeloperation only, as will be hereinafter explained fully.

As a result of the attraction of the armatures IBI, due to theenergization of the relay I33, electrical circuits are established fromthe contact lugs 22 of-transmitter B, through the conductors I06,through the armatures I01, and through the conductors I08 to the B codesegments 82 of the segmented distributor ring I3. It may also i be seenthat the contact lugs 22 of transmitter A are connected directly overthe conductors HD to the A code segments 82 of the segmenteddistributorring 13,

It is to be, further noted (Fig. 1) that when the brush arm Iii bridgesthe stop segment 83 and the solid ring I2, the cam 18 on the bottom ofthe brush arm shaft IE will be so positioned that its h gh point I9 willbe in engagement with the follower roller 81, thereby causing theoperating lever 86 to assume its extreme counterclockwise position, asviewed in Fig. 1, which results in the extended portions 89 and 99 ofthe operating levers 86 and 91, respectively, being in engagement(through set screws 90 and I) with the downwardly extending lugs 35 ofthe bails 32 of both the transmitters A and B. This results in the twobails 32 being rotated in a counterclockwise direction about the pivotrods 33 to a position in engagement with the downwardly extendingportion 3! of the tape feeler levers I2, thereby causing the tape feelerlevers I2 to be moved to and held in their maximum clockwise positionwith the tape pins It retracted downwardly and held out of engagementwith the tape thereover.

10 Therefore, as previously mentioned, the tape may be advanced duringthe stop impulse.

Referring again to Fig. 2, it may be seen that when the apparatus is putinto operation by means of closing the switch in the motor circuit, thusimparting motion through the gear TI to the brush arm shaft 16 and thusto the brush arm 14, the brush arm upon leaving the stop segment 83 willfirst rotate over the special seg ment 84. Inasmuch, as previouslymentioned, as the special segment 84 is connected to the groundedbattery IH, as the brush arm passes thereover potential will betransmitted over the line conductor H9. Therefore, as also previouslymentioned, the special segment 84 at this time acts as a continuation ofthe stop segment. As the brush arm I l passes from the special segment84 to the start segment 8!, a no-current condition will exist on theline conductor H9. This is true because the conductor H8, which isconnected to the start segment 8i, does not at this time establish anyelectrical c rcuit, so there Will be no battery connected to the startsegment BI and therefore no potential will pass to the line conductorH9. This condition exists in neutral operation; that is, where thetelegraphic communication is dependent upon marking and spacing impulsescomposed of current and no-current, respectively.

The result of the brush arm IA passing over the start segment 8| is, aspreviously mentioned, to cause a no-current condition on the'lineconductor H9. Such a condition results in the line relays at the d stantstations PA and PB being ole-energized, thereby conditioning theprinters at those stations for operation, Thereafter, as the brush armI4 rotates over the code segments 82, marking or spacing currents willbe transmitted to the line conductor H9, depending on the code s gnalswhich are perforated in the tape in transmitters A and B. That is, inthe event that there is a perforation in the tape, the associated pin I4will move upwardly passing through the perforation, the feeler lever I2will be moved in a counterclockwise d rection, Fig. 1, or a clockwise drection as viewed in Fig. 2, resulting in the contact arm Il associatedwith that particular feeler lever l2 being positioned in engagement withits associated lower electrical contact I9 and causing a marking impulseto be transmitted over the line conductor H9. In the event that there isno perforation present in the tape the sensing pin I4 cannot passtherethrough and the feeler lever I2 will be held in its clockwiseposition, Fig, 1, causing the associated contact arm IT to be inengagement with the upper electrical contact l8, which results in aspacing impuise on the line conductor I I9 when the brush passes overthat particular segment on the distributor. It might be mentioned thatthe feeler levers I2 are now free to rotate under the action of theirindividual springs It in the event that a perforation is present in thetape, because as the brush arm I4 passes over the start segment 8i, asprev ously described, the brush arm shaft I6 will likewise rotatecausing the high spot 19 of cam I8 no longer to be presented to the camfollower roll 81, thereby resulting in pressure being relieved from theoperating levers 8B and 91, which similarly no longer exert pressurethrough extensions 89 and 99 to the downwardly extending lugs 34 of thebails 32.

Assuming that the first impulse to be transmitted, which will be fromtransmitter B, is a marking impulse, that is, the first feeler lever I2"has pivoted undertheaction .ofxits associated .zpln I4 entering aperforation in the tape, the :upper contact lever I2, as seenin Fig-2associated with "transmitter B,Wil1 have pivoted in a clockwisedirection. Such rotation causes the-contact'arm [7' associated with thefeeler lever I2 to become engaged with the lower electrical contact I 9.When this coccurs, .an electrical circuit is established whichmaybetraced from the grounded battery II I,through thecommon conductor I i2,through the lower electrical contact I9, through the mov- .ableelectrical contact arm I! now in engagement-therewith, through thespring I6, through the contact lug 22, over the conductor H35,

through the armature IU'I (therelay I33 now being energized), throughthe conductor I88, to segment IE on the segmented distributor ring I3,overthe brush arm I4, through the solidring I2, and'over the lineconductor II 5. In the event thatthere has been no perforation in thetape associated with the particular feeler lever IZjust .described,*thelever would haveremained in its normal position, as shown-in Fig.2.Under this normal condition the movable contact arm iI associated'withthe feeler lever I2 is, referring to Fig. 1, in engagement with theupper electrical contact. However, as the present embodiment is utilizedin a neutral transmission system, the contacts I 8 are not connected inany electrical circuit. Therefore, for convenience sake, they ,ihavenotbeen'shown at all in Fig. 2. The result of such is that whenthecontact arm I1 is in its upper position in engagement with electricalcontact I8, no circuit is established and therefore, as brush arm I4passes over the particular segment associated therewith, there will be ano-current or spacing condition on the line conductor 9. The abovedescribed conditions exist throughout the rotation of brush armshaftliiand therefore-brush arm I4 passes over-all ten of the code segments82. That is, as the brush arm 14 rotates over the segments .82successively either a current or a'no-current condition will exist onthe line conductor I I9'at that particular time, depending on whether aperforation existed in the tape for a particular feeler lever I2 or not.In the time that the brush arm '14 takes to make a complete revolutiontwo complete signals have been transmitted over the line conductor I I8,one

.Efromeach ofthe transmitters A and B.

When the brush arm 14 completes the revolution described above and'reengages the stop segment 83, a marking impulse will be transmittedover the .line conductor H9 from the grounded battery .III as previouslydescribed, and, under the control of-thehigh portion I9 of the cam 78,the-bails 32 will beoperated-to cause the selected pins I4 to bemovedfrom engagement with the tape. At this time, as previousl mentioned, thetape stepping levers 25 will also be pivoted causing the associatedpawls 26 to rotate the ratchets 21 one step, causingthe tape feed wheels29 to be likewise rotated and the tapes to he stepped a distance-equalto the .distance between adjacent lines of transverse perforations.Thereafter the whrush arm I4 will once againpass over the start segment8|, a .no-current condition will exist on the line conductor I I9, aspreviously described, andthe.apparatusis-conditioned for a'second cycleof operation.

, It .is "contemplated .in the present invention has been started. Thus,the brush arm I4 does .not stop when itis desired to stop transmissionthe line conductor the printers PA and PB at the distant stations havenot been able to receive their particular code signals. That is, thesignals have not been clear enough, or have been too distorted, or lostcompletely, so that the improper signals or no signals at all arereceived at the distant station.

Under'the-condition just described, which information would be conveyedto the operator of the transmitting station in some manner, the operatorwould manually pivot the switch-over lever .58 in a counterclockwise:direction, as viewed in Figs. 1 and 2. It is to be noted that when theswitch-over lever-58 has been positioned in either of'its positions itwill be held there as a result of a detenting action on the part of thetoggle switch 56 until such time as it may be manually operated to theother of its positions. The result of such an operation, as ,seen inFig. 1, is that the upwardly extending lug 60 will cause the spring 62to be extended, resulting in the bell crank lever composed of the arms48 and 49 being pivoted in a counterclockwise direction. The result ofsuch rotation of the bell crank lever is that the arm 48 movesdownwardly, causing it to be placed, and especially its engagingshoulder 51, in blocking position with respect to the bail -32 oftransmitter B. That is, assuming that the bail is in its extremecounterclockwise position with the feeler levers I 2 pivoted to theirmaximum clockwise position, as viewed in Fig. 1, with the pins I4 out ofengagement with the tape, the shoulder 51 of the arm 48 will engage theforwardly extending lip 56 of the top of the bail 32, thereby preventingthe bail from moving forwardl when the ball 32 would ordinarily beallowed tomove because of the cam 18 no longer presenting its highportion I9 to the roller 81 and thus controlling the operatin levers 86and 91. It may be seen from the drawings that the switch-over lever maynot be operated to block the bail 32 under any other condition than whenthe bail 32 is in its maximum counterclockwise position. This isobviousby referring to Fig. 4, wherein the switchover lever and bailare morecleaily shown. In the event that the ball 32 were in its clockwiseposition, as viewed in Fig. 4, and the switch-over lever 58 wereoperated, the arm 48 would rest on top of the lip 56 of the bail andtherefore the shoulder .51 would not act to block the bail 32 byengagement with the forwardly extending lip 56.

Fig. 4 alsodiscloses, in dotted line, the relative position of the bellcrank lever comprising the arms 48 and 49 with respect to the bail 32after the switch-over lever 58 has been operated, thereby moving thebell crank lever in a counterclockwise direction. Thus it may be seenthat when the switch-over lever 58 is moved in a counterclockwisedirection about the pivot point 59, the bail 32 associated withtransmitter 13 will be blocked out so that the pins I4 will be held intheir downward position, thus preventing any engagement with the tapepassing thereover.

l3 This will be the unoperative position of transmitter B.

Likewise, upon movement of the switch-over lever 58 to its maximumcounterclockwise position the upwardly extending flanges 6i at the rightend of the switchover lever will cause the operating lever 64 of thetoggle switch 66 to be moved in a clockwise direction, thereby causinthe operated lever 61 to be cammed clockwise, thus allowing the movableelectrical contact 68, through its inherent resilience, to move awayfrom the contact 69 thereby breaking the electrical circuit at thispoint. Again, if we assume that the brush arm 10 i on the stop segmentwith the high portion of the cam IS in engagement with the followerroller 81 it may be seen that the movable contact arm I02 is inengagement with the electrical contact I04 in this position. The lockingbattery previously described as being established from the D. C. sourceI2I to the relay I33 over the conductors I22, I24, and through the witchcomprising the electrical contact arms 68 and 69 will no longer beavailable for the relay I33 inasmuch as the latter contact pair has nowbeen opened. Thus, during the stop interval, the relay I33 will bedeenergized and the armatures I36, H6 and I01 will no longer beattracted thereto.

In the event that the operator operates the switch-over lever 58 duringthe time that the brush arm 14 is traversing any of the code segment 82the contact arm 68 will open at the contact arm 69 and thereby break theelectrical circuit at this point. However, at any time other than whenthe brush 14 is on the stop segment the high portion 10 of the cam 18will not be presented to the cam follower roller 81 and thus theoperatin lever 86 will be in a clockwise position. When the lever 86 isso positioned, its extended portion 89 (and through the insulatedmember. IOI) the contact swinger I02 will likewise be positionedclockwise. The swinger I02 will not be in engagement with the contactI04 but instead will be in engagement with the contact I03, thusestablishing an electrical circuit, at the time when the brush arm 10 isnot on the stop segment, which may be traced from the D. C. source I2I,through the conductor I22 to the junction point I23. through a conductorI38, through the contact I03, through the swinger arm I02, through theconductor I to junction point I21, through the conductor I31, throughthe armature I36, through the conductors I3! and I32, through the coilof the relay I33 and over the conductor I34 to the D. C. source I2I.

. Thus, even though the switch-over lever 50 has been positioned forsingle transmission and the contacts 60 and 69 opened, a locking circuitwill still be established for the relay I33 in the event that the brusharm 10 is traversing any of the code segments 82 or the start segment8!. Such a condition has been provided so that if a switchover occursduring the time that the brush arm is traversing any of the codesegments the signal being transmitted at that time will not beobliterated or lost, but instead change-over may occur at such time onlyas no signal is being transmitted over the line conductor I I9.

The result of the falling off of the armatures I01 is to break thecircuits between the conductors I06 and I08, and instead establish acircuit between the conductors III] and the conductors I08. It may beseen from F g. 2, that when this occurs the adjacent A and B segmentsare connectedtogether electrically through the conf of the code segments82.

ductor I08, the armature I01, and the conductor IIO to the contact lug22 of transmitter A for the B segment, and from the A segment directlythrough the conductor IIO to the contact lug 22. The result of this isthat the A and B code segments 82 are no longer separate with each beingconnected to a different tape transmitter, but instead are now bothassociated as single segments with a single tape transmitter. Thisoccurs for all of the ten segments and results, instead of tenrelatively small segments, in five normal sized segments now beingassociated with a single tape transmitter.

As previously mentioned, the relay I33 may only be de-energized when thebrush arm 14 is on the stop segment 83. This has been provided so thatthe armatures I01 may only be operated to connect the B segments to theA segments (thus simulating five large segments) during the stopcondition of the apparatus. If this were not true and such a witch-overoccurred during the rotation of the brush arm over the code segments 82,thereafter as the brush passed over the B segments it would no longertransmit impulses from transmitter B over the line conductor, thusoccasioning the loss of a signal in transmission over the line conductorH9. Thus, by providing the switch-over during the stop interval only,such a condition will not occur and no signal will be lost.

As was previously mentioned the armature H6 also falls away upon thede-energization of the relay I 33. The result of such condition is thatthe small segment 34 which previously had been connected over conductorII1, over armature H6, through short conductor us, and over conductor II3 to the stop segment 83 will instead now be connected over conductor II1, through the armature H6, and over the conductor H0 to the startsegment 0!. Thus the small segment which previously augmented the stopsegment 03 will now be utilized to augment the start segment 6! instead.As was set forth hereinbefore, this segment 84 is approximately one-halfthe size of any The necessity for this switch-over from the stop to thestartsegment is necessary because under the two-channel operation themaximum impulse occurs approximately at the half way mark of theindividual code segments 82. Now then, upon switch-over, so that the Aand B segments are now consolidated into a single segment, it isdesirable that the maximum signaling point occur approximately at thehalf way position of the combined segment which would be approximatelyat the point where they are separated by insulation. Inasmuch as thisshift in maximum impulse point has occurred with respect to the fivecode segments,

it becomes necessary to make some sort of a shift with respect to thestop segment 63 and the start segment iil. Thus, by having the extrasegment 84, which is approximately the size of one-half of one of thesmall code segments 82, when the two adjacent code segments 82 arejoined together and the maximum impulse point is shifted onehalf of oneof the small code segments, a similar shift is made with respect to thestart and stop segments and a similar relative maximum impulse pointwill occur with respect to them. Such is necessary in order that theorientation mechanism of the A printer not be reorientedfor singlechannel operation to maximum impulse point but instead may utilize a,single setting for either single or two channel operation. 7

Transmission will now occur over one of the tape transmitters onlyforsuchia period of time :as it "is desirable.

Thereafter, assuming that good signaling conditions again exist, theoper- 58 in a clockwise direction, as viewed in Fig. 2, which results ina pivotal movement of the switch-over :lever about the point '59.Referring to Fig. 1, it may be seen that when this occurs the upwardlye'xtendinglug Gil will move inwardthis time the bail 32 of transmitter13 will not be immediately released for operation. Atsuch time as thebail 32 is rotated to its extreme counterclockwise position under theoperationof the extended portion '99 in engagement with the lug 34extending downwardly from the bail, which oc- :'curs atsuch time as thebrush arm is is on the stop segment 83 and the high portion l9 of thecam 78. is presented to the operating lever -85, the upper electricalcontact arm 53 will exert suflicient pressure to cause the arm 48 of thebell crank lever composed of the arms 58 and 49 to movein aclockwisedirection thereby freeing the forwardly extending lip 56 of thebail 32 from the shoulder 57 ofthe arm 48. This latter occurs,

even though the bail 32 has been held in an arrested position, becausethere is a slight amount of movement of the bail 32 during the operationof the operating lever Bl and its extended portion 99 when the followerroller 8'! is in engagement with the apex 79 of the cam 18. However,

this movement is not sufficient to cause the bail 32 to be freed in anyother position than when the bail is rotated to its maximumcounterclockwise position. By'referring to Fig. 4, it may be seen thatthe forward edge of the extending lip 56 of the bail 32 is cut at anangle, as is the faceof the shoulder of the arm 48. Because of theangular surface of the lip 56 and the shoulder 5! the bail 32 will notbe released from looking position at any time other than when the apex79 of the cam 78 is presented to the operating lever 8b which occursonly when the brush arm "M traverses the stop segment 83. At this lattertime the bail 32 is moved to its maximum counterclockwise position whichis the only time that there is sufficient clearance for the angular faceof the shoulder 57 to pass the angular face of the lip 56. The lever 58cannot be moved from looking position at any other time because theforce exerted by the lever resetting contact spring 53 is not suiiicientto overcome the force exerted on the bail, in a clockwise direction, bythe tape sensing mechanism which would be necessary to unlock the bail.

Thus, under this condition, the transmission will occur once again fromboth transmitters A and B over their respective segments 82 rather thanfrom transmitter A alone over the double segments as just described. 7

By referring to Fig. 5, a switch-over lever may be seen which operatessomewhat differently than the switch-over lever and associated partsjust described. In the modified device the operating arm and bailblocking lever are two separate members, which are identified by thenumerals J4! and M2, respectively. The blocking lever 142,

which is pivoted about a shaft M similar to that in the preferredembodiment, has a sidewardly extending lug 5G and a shoulder 57 therein,and

is also provided with a rearward and downwardly extending projection I43which has oneend of a- .ator may manually operate the switch-over leverspring 154 securedithereto. The operating lever MI is also pivoted atpoint ill and has the opposite end of the spring M l secured thereto.Toward the downward extremity of the operating lever Ml is a secondspring secured thereto, the opposite end of which passes through theupwardly extending 'lug 60 of the switching lever 58, similarly asdescribed with respect to Figs. 1 and 4. The'operating lever i 'll alsohas a sidewardly extending lug l4? at the lower portion thereof which isassociated with a bolt i 13 which is screwed through the upwardlyextending lug iii} of the switching lever 58 and securedin place thereinby means of a nut'on the opposite side thereof.

In operation, assuming that there has been two channel transmission andit is necessary to switch over to single channel transmission, the

operator would manually operate the switch-over lever 53 to itscounterclockwise position which would result in the upwardly extendinglug 60, Fig. 5, being moved toward the right. This would result in thespring M6 being extended, causing the operating lever 14! to'be pivotedabout pivot point it? in a counterclockwise direction. When this occurs,an extending lug hi9 which is a part of the operating lever Ml and whichis so positioned as to overlie the top of the blocking lever hi2 comesinto engagement with the operating lever Hi2 and tends to force it in acounterclockwise direction. Assuming that the brush arm is is on thestop segment and the ball 32 in a position as shown in Fig. 5, theoperating lever I42 will immediately 'move downwardly under the urgingof the lug M9 and thus present its shoulder 5? in blocking relation withthe inwardly extending lip 5b of the bail 32. In the event that the bail32 were in its clockwise position, thereby underlying the bottom ofthe'blocking lever [52, the blocking lever would not at this time moveto locking position but instead would rest on the top of the lip 56until such time as the bail 32 moved rearwardly to its position as shownin Fig. 5. Howeven'because the spring M6 was extended and tending torotate the operating lever M2, and thus through the lug M9 impart motionto the blocking lever I42, the blocking lever will operate as soon asthe bail moves to its normal position.

Assuming now that single channel operation has been utilized for such atime as is necessary, and that signaling conditions are now of such adegree that two channel operation may again be resumed, the operator maymanually operate the switch-over lever 58 to its clockwise position.This results in the upwardly extending lug '60 moving toward the left,as viewed in Fig. 5, which allows the spring M6 to resume an unextendedposition. However, the bolt Hi8 will also move toward the left, Fig. 5,and engage the sidewardly extending lug Ml of the operating lever Ml,thereby causing the operating lever Ml to be'pivoted in a clockwisedirection. This not'only removes pressure of operating lever l il uponblocking lever I42 through the overhanging lug Hi9 but also causes thespring M l to be extended. The result of the extension of the spring M4is that it exerts pressure tending to move the blocking lever M2 in aclockwise direction, through the rearwardly extending lug MS-thereof,which allows the blocking lever I62 to move free from engagement withthe'bail 32 under'similar conditions as expressed in relation to thepreferred embodiment. Therefore it may be seen that in the embodiment.shownin 5; it is not neces- 17' sary to depend on the resilience of theelectrical contact arm 53 to move the blocking lever I42 from blockingengagement with the bail 32, but instead it is positively removed bymeans of the spring I44.

It is self-evident that a switch-over lever such as lever 58 and itsassociated bail blocking elements need only operate in conjunction toblock out the bail 32 of one of the tape transmitters, inasmuch as whenit is operated, single channel operation, is desired and so it isnecessary that one of the tape transmitters still operate under thiscondition.

During two-channel transmission it maybe necessary for some reason, suchas the tape being exhausted in one of the tape transmitters only, toblock out the operation of one or the other of the tape transmitterswithout switching to single channel operation. For this reason thethreearmed lever 36 has been provided for each of the tape transmitters.Referring to Fig. 1, it may be seen that when an operator manuallypositions the three-armed lever 35 in a clockwise position, throughpressure being exerted on the arm 38, the forwardly extending arm 39will engage the lug 50 extending sidewardly from the arm 48. Under thiscondition the arm 48 will be forced in a counterclockwise direction, andoperating as previously described with respect to the opera tion of theswitch-over lever 58, will cause the shoulder 51 of the arm 48 to engagethe forwardly extending lip 56 of the bail 32, thereby blockingoperation of the bail. The associated spring 43 has been provided sothat in the event that the bail 32 underlies the arm 48 at the time thatthe arm 38 is operated the spring 43 will act as an overthrow spring andsupply constant pressure to the sidewardly extending lug 58, through theforwardly extending arm 39, so that when the bail 32 moves to itsextreme rearward position when the brush arm I4 is on the stop segment83, the arm 48 will then be operated to present its blocking shoulder 51to the lip 56 of the bail 32. Likewise, when the arm 38 is operated toits position, as shown in Fig. 1, whereby it is not blocking the hail,the spring 43 acts to hold the three armed lever 35 in its extremecounterclockwise position. A pin 46 has been provided which will beengaged by the downwardly extending arm 40 of the lever 38 when the arm38 is positioned in a counterclockwise direction, and which with thepressure applied thereto by the spring 43, tends to limit thecounterclockwise movement of the lever 36.

As mentioned above, one of these lock out levers is provided for each ofthe tape transmitters A and B, both operating similarly with respect tothe bail blocking lever 48. Thus an operator may, upon manual operationof either of the levers 36, cause its associated tape transmitter to beheld in a locked out condition and therefore preclude the transmissionof signals from that particular tape transmitter. In the embodimentshown in Fig. 1, when the operator moves the arm 38 to its extremecounterclockwise position, the upper electrical contact arm 53 willcause the lever 48 to be moved from blocking position, as previouslydescribed.

As was previously mentioned, an electrical contact pair 53, 54 underlieseach of the bail blocking arms 48 in such a manner that when theblocking arm 48 is operated to preclude operation of the associated tapetransmitter, through a lock-out of the baili32, the upper electricalcontact 53 is positioned in engagement-with the lower electrical contact54 thereby completing an electrical circuit. By referring to Fig. 2, itmay be seen that if only one of the blocking levers 58 is operated tocause the associated contacts 53, 55 to close, no complete circuit willbe established. However, in the event that both of the blocking levers48 are operated, thereby closing both of the contact pairs 53, 54, anelectrical circuit will be established from the grounded battery III,over common conductor H2, over conductor M3 to junction point I5I, overconductor I52, through the contact pair 53, 54 associated withtransmitter B, over the conductor I53, through the contact pair 53, 54associated with transmitter A, and over conductor I54 to the lineconductor H3. Such an electrical circuit has been provided, because inthe event that both the transmitters A and B were to be held in theirblocked or unoperative position, all of the tape feeler levers I2 willbe held in their counterclockwise position, as viewed in Fig. 2, therebycausing their associated contact arms I! to be in engagement with theupper electrical contact I8 (Fig. 1). As has previously been de scribed,when this occurs a spacing condition exists on the line conductor I I 9,inasmuch as a nocurrent condition exists at this time. Therefore,inasmuch as the brush arm 14 continuously ro tates, once its drivingmotor has been started up, it will continue to rotate until such time asthe driving motor is shut off, and as the brush arm 14 passes over thestart segment 8! and all of the code segments 82, a spacing conditionwould exist on the line. Inasmuch as such a spacing condition wouldactuate the printers PA and PB at the distant station to causecontinuous blank spaces to be recorded on the printer, it is desirableto provide means whereby this will not occur. Therefore at such time asthe transmitters A and B are both caused to be unoperative, a markingcondition will exist on the line conductor H3, being supplied withpotential from the grounded battery III, over the circuit describedimmediately above. In the normal telegraphic system when a markingcondition exists on the line, the printers at the distant station willnot be actuated until such time as a spacing start impulse istransmitted. Thus, if marking is continuously applied to the lineconductor H3, the printers PA and PB will not be initiated intooperation during this condition. However, as soon as one of the tapetransmitters is placed in operative service by means of a movement ofthe three-armed lever 36 associated therewith, the electrical contacts53, 54 associated with that tape transmitter will then open and theshunting circuit for applying continual marking battery on the line H9will no longer exist.

It is to be remembered that the prior description has been confined totelegraphic operation with neutral signals; that is, signals comprisingcurrent or no-current condition on the line conductor. I-Iowever,inasmuch as certain telegraph systems operate on polar signals, that is,signals comprising positive and negative battery or polarity on the lineconductor, a modification has been shown in Fig. 3 wherein suchtelegraphic communication is possible. It is to be noted that Fig. 3does not show the complete tape transmitters A and B or the completedistributor, such as was shown in Fig. 2. It is believed, however, thatinasmuch as the remaining elements necessary for Fig. 3 to make itsimilar to Fig. 2, that is, complete tape transmitters A and B and acomplete distributor, is obvious to one skilled in the art and inasmuchas they are the same as the nmates 19 unit shown, a repetition isunnecessary. Inas much as the component parts of the apparatus necessaryfor polar operation are substantially similar to those for neutraloperation, numerals will be used in Fig. 3 similar to those of Fig. 2wherever possible.

As only two of the code segments 82 have been disclosed, one associatedwith transmitter A and the other associated with transmitter B, thepolar operation description will be confined to these segments.Likewise, inasmuch as only two tape feeler arms l2 have been disclosed,one connected to each of the above-mentioned segments and one associatedwith transmitter A and the other with transmitter B, the followingdescription will be confined to these tape feeler levers I2. Anassumption will be made for explanation purposes, that the feeler leverI2 shown for transmitter B is in its spacing position, that is, has notsensed a perforation in the tape, and that the tape feeler lever I2associated with transmitter A has sensed a perforation in the tape andmoved to its marking position.

Inasmuch as in the rotation of the brush arm I4 it passes over the codesegment 82 associated with transmitter 13 prior to passing over thesimilar code segment 82 associated with transmitter A the followingdescription will be-made on such a basis.

In the description immediately following, it is to be assumed that thelever 43 associated with the B transmitter is in its unoperated orextreme clockwise position, as viewed in Fig. 3, rather than as shown.Under such a condition the contact pair 53, 54 and the contact pair I69,I94 would be opened rather than closed, whereas the contact pair I69,I68 would be closed (normal positions). The lever (Btransmitter) hasbeen illustrated as shown in Fig. 3 in order to disclose more clearly acondition to be described hereinafter.

As was mentioned above in the present example, it is assumed that thefeeler lever I2 shown for transmitter B is in its spacing condition,that is, the condition when there is no perforation in the tape oppositethe pin I i of that particular lever. Under such a condition the feelerlever I2 is held in its normal position; that is, extremecounterclockwise position, as shown in Fig. 3. When the feeler lever I2is in this position, its contact arm I! associated therewith is inengagement with the upper electrical contact I8, as shown. The result ofsuch contact engagement is the establishment of an electrical circuitwhich may be traced from grounded positive battery IBI, over a conductorI62, over an armature I53 of a relay I 64, over a conductor I66, over aconductor I67, through an electrical contact I68 which is normally inengagement with a movable swinger arm I 59, through the swinger arm I69,over a conductor III to the contact point I8, through the contact arm I?in engagement therewith, through the spring I6, through the contact lug22, over the conductor I06, through the armature III! of relay I35 (inits left-hand position due to the energization of therelay I33 duringtwo-channel transmission) and through the conductor I 08 to the B codesegment 82, through the brush arm "Hi, through the solid ring I2, andover the line conductor H9 to ground at the distant station. Thus, inthe condition just described spacing or positive potential has beenapplied to the line conductor H9.

Immediately after the brush arm 'l ttraverses the B code segment 82 justdescribed, it passes over an A code segment tzassociated withtransmitter A. Inasmuch as we have assumed that the feeler lever I2 oftransmitter A, shown in the drawing, was in marking position, that is,its pin It had passed through a perforation in the tape and the lever I2was pivoted in a clockwise direction, its associated contact arm I? willbe in engagement with the lower electrical contact I9. Thus, anelectrical circuit may be traced from negative grounded battery I12,over a common conductor I I3, through the electrical contact Ii),through the contact arm I'I, through the spring It, through the contactlug 22, through the conductor IIII to the A segment 82, over the brusharm 7 over the solid ring 12, and over the line conductor III) to groundat the distant station. Thus, it may be seen that a marking or negativebattery condition will exist on the line conductor IIS during thetraversal of the A segment IIZ by the brush arm I4.

. t is to be seen that transmitter A has a similar contact I63 normallyclosed at the movable swinger I69, so that in the event that any of thefeeler levers I2 associated with transmitter A were in their spacingposition, that is, with the pins It not entering a perforation in thetape, spacing battery .IfiI would be supplied to the code segment 82associated with transmitter A over a conductor I14. Likewise, in theevent that any of the feeler levers I2 of transmitter B was in itsmarking position, that is, with the pins entering a perforation in thetape, negative battery II?! would be supplied directly over conductorI73 to establish a negative battery or marking condition on the lineconductor "H9 through the B code segments 82 associated with transmitterB.

It is to be noted that in polar operation of the apparatus, Fig. 3,there is also provided the switch-over means through a relay I33 (notshown) and the armatures Hi1, so that in the event that it is desired totransmit over a single channel rather than the two channels, suchchange-over may occur. Likewise, an armature I6 is provided, associatedwith the switch-over of the short segment 84 from the stop segment 33 tothe start segment BI when operation over a single channel is desired,rather than twochannel transmission. The operation of this is similar tothat described with respect to neutral operation.

It is to be noted that negative marking battery I72 is supplied over aconductor I16 to junction point I'll, and over a conductor I78 to the'stop segment 83 of the segmented distributor ring. Thus, when the brusharm 14 is bridging the stop segment 83, marking battery will be appliedthrough the brush arm '14, through the solid ring i2, and over the lineconductor IIS. Likewise, when the brush arm I I is on the start segment8i, positive spacing battery is applied from grounded battery IBI, overconductor I52, through armature I63, over the conductor I65, over theconductor I79, and over the conductor It! to the start segment SIwherefrom it is applied to the brush arm 14 and the solidring I2 to theline conductor H9. Such electrical circuits are necessary, inasmuch asin polar signal operation it is necessary that there be a marking ornegative battery condition continuously on the line, and which is brokenby .a start or positive battery spacing impulse. Likewise, the codeimpulses may be either positive (spacing) or nega- 21 tive (marking),depending on the perforations in the tape.

In the event that both transmitters A and B were to be shut down forsome reason, the brush arm I4 would still continue to rotate over thesegments of the distributor face and if nochanges were made negativemarking battery would be transmitted over the line conductor I I9 as thebrush arm It rotated over the stop segment 83, whereas positive spacingbattery would be transmitted over the line conductor H9 as the brush Mrotated over the start segment BI and all of the code segments 82. Thiswould result in the initiation of operation of the receivers at thedistant station which would cause them to space every time that thebrush arm I4 completed a revolution. It is obvious that this is not a.good condition as the receivers would not have any stop condition. Inorder to prevent such an occurrence, a pair of contacts 53, St

has been provided for each of the tape transmitters similarly to thatdescribed with respect to Figs. 1 and 2. Therefore, at such time as thetape transmitters are shut 01f by means of the operation of thethree-armed shut-off levers 36, the downward movement of the bailblocking levers 48 will result in the contacts 53, 5 3 being closed.When these latter contacts are closed an electrical circuit may betraced from local source of D. C. power I82, over the conductor I83,through the now closed contact pair 53, 54 associated with transmitterB, over a conductor I3 8, through the closed contact pair 53, E iassociated w th transmitter A, over a conductor I86, through the coil ofthe relay I54, and over a conductor I8! back to the source of D. C.power I82. As a result of this circuit being established the relay I64will be energized, Upon the energization of the relay I64, the armaturesI63 and I89 are attracted thereto, which has the effect, as may be seen,of opening one circuit and closing a second circuit. The electricalcircuit which is opened is the one previously described to the startsegment BI and the spacing contacts l9; namely, from the positivespacing battery IGI over the conductor I62 and through the armature I63.Therefore, the start segment 8i and the spacing contacts I9 will nolonger be supplied with spacing battery.

Upon the armature I89 being attracted due to the energization of therelay I64, an electrical circuit is completed which supplies negativemarking battery M2 to the line conductor H9 by means of the conductorI16, the armature I89, and a conductor I9I. Thus, it may be seen thatnegative marking battery is supplied to the line conductor I I9 in sucha manner that it by-passes the distributor completely, and therefore isnot dependent on the operation of the latter to keep the receivers atthe distant station in an unoperative or stop condition,

In the event that only one of the tape trans- I mitters is shut down bythe manual operation of the shut-01f lever 36, and the subsequentlooking of the bail 32 to an unoperative position by means of thelook-out lever 48 associated therewith, the other contacts 53, 54associated with the still operative tape transmitter will not be closed,and therefore no electrical circuit will be established for theenergization of the relay I64. Such a marking on the line by-passcircuit is not necessary or warranted under this condition, inasmuch asthe second tape transmitter must still transmit message signals over theline conductor I I9, and therefore it is necessary that both markmittersis caused to be unoperative, by means of the manual operation of theshut-01f lever 36, as the brush arm it rotates over the code segments 82associated with that particular tape transmitter, and inasmuch as theassociated feeler levers iii will be held in their spacing position inengagement with the upper contact I8,

spacing battery lfil would ordinarily be applied to the five codesegments 82 of that tape transmitter, resulting in an allspacing orblank signal being transmitted over the line conductor H9. Inasmuch asonly a single stop and start segment is provided to operate for both ofthe tape transmitters and for the two printers at the distant station,both of the printers would be operated but one would receive a blanksignal, In certain telegraphic systems the blank or all spacing signalis utilized solely for switching or station selection purposes.Therefore, it would be disadvantageous to have such a condition exist;in order to offset such a possibility occurring, apparatus has beenprovided whereby spacing signals will not be transmitted over the lineconductor when one of the tape transmitters is in its unoperatedcondition.

As previously mentioned, a swinger contact arm IE9 is provided which isnormally in engagement with the electrical contact T68. This swinger armI 69 is connected by an insulated section I93 with the contact arm 53which is under the control of the lock-out lever 48. Therefore, in theevent that the look-out lever ii; is operated to lock the bail 32 of oneof the tape transmitters, the swinger contact I69 under the control ofthe insulated section I93 will be moved from engagement with theelectrical contact I58 and instead will be positionedin engagement withan electrical contact I5 1. The contact 59 1. is normally open and suchengagement will only be made during the time that the brush arm M is onthe stopsegment, as described With regard to prior descriptions.Assuming thatv the lowermost blocking lever iii in Fig. 3, associatedwith tape transmitter B, had been operated. by means of the three-armedblock-out lever 36 being manually rotated in a clockwise manner, theinsulated section I93 will be moved downwardly under the control of theelectrical contact arm 53 and the movable contact swinger I69 will beremoved from engagement with electrical contact E83 and positionedinstead in engagement with the electrical contact I94. As a result ofthe movement of the electrical contact, spacing battery which wasformerly supplied from grounded battery It I, over conductor I62,through armature 153, over conductor I66, through the electrical contactI68, through the electrical contact swinger I69, over the conductor IIIand therefore to the spacing contacts I8, will no longer be possibleinasmuch as the electrical circuit just traced is broken between theelectrical contact I68 and the swinger I as. Instead, negative markingbattery will now be supplied from the grounded marking battery 1T2, overthe conductor I535 to the electrical contact I94, through the swingerarm I69, and over the conductor III to the spacing electrical contactI8. At such time as the tape feeler levers I2 are held in theirunoperated or counterclockwise position, with the contact arm I? inengagement with the spacing contact i3, negative marking battery will besupplied from the contact (8, through the contact arm I1, through thespring 16, through the contact lug 22, over the conductor W6, throughthe armature iB'i, through the conductor 38, andto the B code segment82. Therefore, under this special condition which would ordinarilytransmit a blank or all spacin signal over the line conductor I I9, fivemarking impulses or a letters combination will be transmitted instead.The letters combination transmitted over the line conductor will notcause any switching or station selection, inasmuch as the normaltelegraphic system does not depend on this combination for such functionto occur.

It is to be understood that the above condition exists only at such timeas the block out lever 48 is operated under the control of thethree-armed lever 36 to lock out the associated ball 32 and thereby holdthe tape sensing levers [2 of that particular tape transmitter in anunoperated position. This condition will not exist under normaltransmission as at such time a blank signal may actually be sent outover the line conductor 5 Hi from the tape, or during such time as thebrush arm 14 is on the stop segment 83 and all of the tape feeler levers12 are held in their unoperative position so that the tape may bestepped. Such is obvious, because during these two conditions, theblock-out lever 48 will not be operated, and therefore, the electricalswinger arm l69.will be in engagement with the electrical contact I68and not in engagement with the electrical contact I94.

While the above description has been made with respect to transmitter Bonly, it is obvious, inasmuch as both of the tape transmitters aresupplied with a similar contact under the control of the block-out lever48, that if either of the tape transmitters are shut off a letterssignal will be sent by that particular transmitter. This condition doesnot occur when both of the blockout levers 48 are operated, inasmuch asat that time marking battery is applied directly to the line conductorthrough the then attracted armature l89 of the relay I64 as describedabove.

Likewise, even though the two special contacts have been provided,associated with each of the look-out levers 58, to supply markingbattery through the code segments 82 of the distributor when the tapetransmitters are held in an unoperated position, it is still necessaryto provide the relay are when both transmitters are stopped. This isnecessitated because even under the conditions described immediatelyabove and under which marking impulses; would be transmitted from thestop segment 83 and the ten code segments 82, spacing battery wouldstill be transmitted from the start segment 8|, as traced from thespacing battery I51, over the conductor I62 through the armature Hi3,over the conductors 2%, H9, and It to the start segment 8!. Therefore,even with the provisions described above, it is still necessary to havethe relay lfifi operated when both of the tape transmitters are shutdown, to thereby cause the armature I63 to be attracted thereto, thuspreventing the spacing battery from reachin the start segment, which, inturn, upon being transmitted over the line conductor H9 would cause thedistant printers to be operated. Asmentioned before, this isaccomplished by supplying marking battery 183 directly to the lineconductor 1 is, through the then attracted armature I89, therebyby-passing the segmented distributor-completely.

R'eferringback to Fig. 2, the distant printers PA and PB, previouslymentioned, comprise a line relay, a selector magnet, and a groundconnection. It is to be noted in the instant disclosure that the lineconductor H9 does not go directly to the receiving printers PA and PB,but instead pass through a pair of regenerativ repeaters i9? and itii.These regenerative repeaters i9? and 38 are standard regenerativerepeaters as disclosed in U. 5. Patent No. 2,105,173, issued to W. J.Zenner et al. on January 11, 1938, with the exception that theirorientation devices are so positioned that the regenerative repeater 59?will only be responsive to a particular group of code signals, forinstance those transmitted from transmitter A, whereas the regenerativerepeater i98- will be responsive only to a second group of signals, suchas those transmitted from transmitter B. However, both of theregenerative repeaters it? and Q8 are responsive to .the single startand stop impulses transmitted over the line conductor.

The signals received by the regenerative repeater will be repeateddirectly to the individual printer PA or PB associated therewith. Thus,the results of such a provision is that standard telegraphic printerssuch as are disclosed in U. S. Patent No. 1,904,164, issued to S. Mortonet al. on April 18, 1933, and as described in Bulletin No. 133 issued inGctober 1941, by the Teletype Corporation, Chicago, Illinois, may beused without altering the standard range finder or orientation devicesetting. In this manner the two regenerative repeaters l9? and E98 areresponsive to the incoming signals and thereby retransmit the propersignal group to the proper receiving printer PA or PE. Further, it ispossible by using such regenerative repeaters to not only transmit theincoming signals to the proper printer PA or PB, but also to retransmitthem to a second distant station. Similar equipment would be provided inthe polar operation, as shown in Fig. 3.

However, it is not necessary that regenerative repeaters be insertedimmediately before the printers PA and PB. It is possible to adjust theorientation device associated with the printers disclosed in theabove-mentioned Morton et al. patent in such a manner that two seriesprinters will each be responsive to the stop and start impulses, buteach one will be only responsive to a single group of code impulses.

Although a specific embodiment of the invention has been shown anddescribed, it will be understood that this embodiment is butillustrative and that various modifications may be made therein withoutdeparting from the scope and spirit of the invention.

What is claimed is:

1.'In a start-stop telegraph system, a pair of tape transmitters, adistributor having a plurality of code segments half of which areconnected to each of said tape transmitters in alternate sequentialorder, signal forming means associated with each of said tapetransmitters, a bailassociated with each of said tape transmitters forcontrolling said signal forming means, means associated with saiddistributor for controlling the operation of said balls, and meansoperating to block the operation of one of said bails independently ofsaid distributor associated means thereby rendering one of said tapetransmitters unoperative and to alter the connections between saiddistributor and said tape transmitters whereby the first of said tapetransmitters is disconnected from said code segments of said distributor25 and the other of said tape transmitters is connected to all of saidcode segments of said distributor.

2. In a start-stop telegraph system, a pair of tape transmitters, adistributor having a plurality of code segments half of which areconnected to each of said tape transmitters in alternate sequentialorder, signal forming means associated with each of said tapetransmitters, a bail associated with ea :h of said tape transmittersforcontrolling said signal forming means, means associated with saiddistributor for controlling the operation of said balls, a switch-overlever for controlling the altering oi the connections between saiddistributor and said tape transmitters whereby upon operation one ofsaid tape transmitters is connected to all of said code segments of saiddistributor, and means associated with and under the control of saidswitch-over lever for blocking the operation of said bail associatedwith the other of said tape transmitters whereby said other tapetransmitter is rendered unoperative.

3. In a start-stop telegraph system, a pair of tape transmitters, adistributor having a plurality of code segments half of which areconnected to each of said tape transmitters in alternate sequentialorder, signal forming means associated with each of said tapetransmitters, a ball associated with each of said tape transmitters forcontrolling said signal forming means, means associated with said.distributor for controlling the operation of said bails, and a shut-offlever associated with each of said tape transmitters whereby uponoperation of one of said shut-ofi levers said associated bail is causedto be blocked and said tape transmitter to be rendered unoperative.

4. In a start-stop telegraph system, a pair of tape transmitters, adistributor having a plurality of code segments half of which areconnected to each of said tape transmitters in alternate sequentialorder, signal forming means associated with each of said tapetransmitters, a bail associated with each of said tape transmitters forcontrolling said signal forming means, means associated with saiddistributor for controlling the operation of said bails, a shut-offlever associated with each of said tape transmitters, and an electricalcontact associated with each of said shut-off levers whereby when bothof said levers are operated to cause both of said tape transmitters tobe rendered unoperative said contacts are closed to establish anelectrical circuit to directly apply potential to a line conductorcompletely by-passing said distributor.

5. In telegraph transmitting apparatus, a pair of tape transmitters, adistributor having a plurality of code segments half of which areconnected to each of said tape transmitters in alternate sequentialorder, signal forming means associated with each of said tapetransmitters, a plurality of marking contacts and a plurality of spacingcontacts associated with said signal forming means in each of said tapetransmitters, a bail associated with each of said tape transmitters forcontrolling said signal forming means, means associated with saiddistributor for controlling the operation of said bails, means tonormally transmit spacing potential from said spacing contacts andmarking potential from said marking contacts, means to block one of saidbails whereby said associated tape transmitter is rendered unoperativewith said spacing contacts conditioned, and means under the control ofsaid ball blocking means to cause marking potential to be applied tosaid spacing contacts.

6. In telegraph transmitting apparatus, a pair of tape transmitters, adistributor having a plurality of code segments half of which areconnected to each of aid tape transmitters in alternate sequentialorder, signal forming means associated with each of said tapetransmitters, a plurality of marking contacts and a plurality of spacingcontacts associated with said signal forming means in eachofsaid tapetransmitters, a bail associated with each ofv said tape transmitters forcontrolling aid signal forming means, means associated with saiddistributor for controlling the operation of said bails, means tonormally transmit spacing potential from said spacing contacts andmarking potential from said marking contacts, means to block one of saidbails whereby said associated tape transmitter is rendered unoperative,and means under the control of said ball blocking means to causepotential of an opposite polarity to be transmitted from one of saidsets of contacts.

'7. In start-stop transmitting apparatus, a distributor comprising asolid ring and a segmented ring, said segmented ring including a startsegment, a plurality of code segments, and a stop segment, a brush armfor bridging said solid and segmented rings, means to rotate said brusharm, a pair of tape transmitters each connected to half of said codesegments in alternate sequential order, means to alter said connectionswhereby one of said tape transmitters is connected to all of said codesegments and the other of said tape transmitters is disconnected fromsaid code segments, said latter means being operative to reconnect saidtwo tape transmitters to said code segments as initially described, andmeans to preclude such reconnection at any time other than when saidbrush arm is on said stop segment.

8. In a start-stop telegraph system, a pair of tape transmitters, a ditributor having a plurality of code segments half of which are connectedto each of said tape transmitters in alternate sequential order, signalforming means associated with each of said tape transmitters, a bailassociated with each of aid tape transmitters for controlling saidsignal forming means, means associated with said distributor forcontrolling the operation of said bails, a shut-off lever associatedwith each or said tape transmitters whereby upon operation of one ofsaid shut-off levers said associated bail is caused to be blocked andsaid tape transmitter to be rendered unoperative, and mean to preventsaid unoperative transmitter from being rendered operative except undera predetermined condition of said distributor.

9. In a signal generator, a distributor provided for transmitting codeimpulses and a stop impulse, a pair of signal initiating means eachconnected to said distributor for initiating the code impulses, means toalter said connections whereby one of said signal initiating means isconnected to said distributor and the other of said signal initiatingmeans is disconnected from said distributor, said latter means beingoperative to reconnect said pair of signal initiating means to saiddistributor, and means to preclude such reconnection at any time otherthan during the transmittal of the stop impulse by said distributor.

10. In start-stop transmitting apparatus, a distributor including aplurality of code segments for transmitting code impulses and a stopsegmerit forLt-rensmitting}a td' impulse, a pair of sig'nzilinitiatingmeans each connected 'tofhal! of said code segments, meanstoalter said connec- "tions-whereby one of said=signa1initiatingmeansisconnected to all of -said code segments and the other of saidsignal initiating means'is-disconnected from said code segments, saidlatter means being operative to reconnect said two signal initiatingmeans to saiwcodesegments as initially described; and 'meansto precludesuch reconnection at any time other than dnringthe tor.

The following references WILBUR R. GEMMEL.

REFERENCES CITED are of record in the file of this patent:

10' Number UNITED STATES PATENTS

